The isolation and structure elucidation of cytotoxic and antileukemic compounds will be carried out from a number of plant species including Annona acuminata, Austrocedrus chilensis, Callitris preissii, Hyptis tomentosa, Juniperus phoenicea, Physocarpus opolifolius, Salpichroa tristis, Tabebuia cassinoides, and Tibouchina pulchra. Isolation will be carried out using all applicable techniques, including high performance liquid chromatography were appropriate. Structure elucidation will be done using spectroscopic and chemical methods in some cases, and X-ray crystallography in other appropriate situations.